Spring unit



Nov. 1, 1966 w. v. SLOMINSKI SPRING UNIT Filed Feb. 1, 196 5 [NVENTOR WALTER V. SLOM/NSK/ W E ATTORNEY? United States Patent 3,282,583 SPRING UNIT Walter V. Slorninsiri, lemngton, Ky., assignor to Hoover Ball and Bearing Company, Saline, Mich, a corporation of Michigan Filed Feb. 1, 1965, Ser. No. 429,299 3 Claims. (Cl. 267-107) This invention relates generally to spring assemblies for seating structures, and more particularly to a seating structure spring unit which is an improvement on the structure shown in US. Patent No. 2,480,667 assigned to the assignee of this invention.

In the manufacture of most cushioned seat structures, spring units are mounted in parallel lines across an open frame, with padding and an upholstery cover stretched over the spring units. The spring unit illustrated in US. Patent No. 2,480,667 for forming a seat back structure includes a main load bearing body spring attached at its lower end to a lower frame rail, and a support spring attached to the rear side of the body spring and the upper frame rail. The support spring has a V-shape portion so that it will yieldably resist the loads applied to the body spring which normally tend to move it toward the upper frame rail. The body and support springs are formed of well known zigzag wire which includes transversely extending torsion bars connected by spacer bars and cooperate to provide an accepted spring unit which is neither too hard nor too soft along its full load supporting length. Such spring units are usually attached to the upper frame rail by forming a prong on the end of the support spring which is inserted in an opening in the upper frame rail. Adjacent the prong is a torsion bar which engages the mounting face of the upper frame rail on which the spring is mounted. One serious objection which has been encountered in seat spring units of this type is the noise which sometimes occurs during loading and unloading of the spring unit. This objectionable noise is caused by the squirming of the torsion bar on the mounting face of the frame rail. It is an object of this invention, therefore, to provide a spring unit which is an improvement on the spring unit illustrated in Patent No. 2,480,667 in that it avoids this objectionable noise and is also capable of providing increased load resistance without a corresponding increase in the volume of wire utilized.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims, and the accompanying drawing in which:

FIGURE 1 is a vertical sectional view of a seating structure having the improved spring unit of this invention incorporated therein, and illustrating the spring unit in an unloaded position;

FIGURE 2 is a vertical sectional view like FIG. 1 showing the spring unit in a loaded position;

FIGURE 3 is an enlarged fragmentary sectional view of a portion of the improved spring unit of this invention looking substantially along the line 33 in FIG. 1, and illustrating the assembly of the unit with a supporting frame rail;

FIGURE 4 is an enlarged fragmentary detail view of a portion of the structure shown in FIG. 1 illustrating the direction of the forces applied to the frame rail by the spring unit; and

FIGURE 5 is a vertical sectional view of a modified form of the spring unit of this invention.

With reference to the drawing, the spring unit of this invention, indicated generally at 10, is illustrated in FIG. 1 incorporated in an upholstered furniture seat back assembly 12 which includes an upper wood frame rail 14, a lower wood frame rail 16, and upholstery padding material 18 applied to the rails 14 and 16 and the unit 10.

3,282,583 Patented Nov. 1, 1966 The spring unit 10, in the illustrated embodiment of the invention, consists of an elongated main or body spring 20 and a support spring 22 which is secured to and positioned on the rear side of the body spring 20. Both springs 20 and 22 are illustrated as being formed of sinu ous wire having substantially parallel transversely extending torsion bars 24 and oppositely facing spacer bars 26 which connect the opposite ends of each torsion bar to the ends of the adjacent torsion bars 24. It is to be understood that the springs 20 and 22 can be formed of either sinuous wire or formed wire, both of which are well known, sinuous wire being illustrated in the aforementioned US. Patent No. 2,480,667 and formed wire being illustrated in FIGS. 4 and 5 in US. Patent No. 3,095,189, also owned by the assignee of this invention. Both sinuous wire and formed wire have transverse torsion bars adjacent ones of which are connected by spacer bars. Both types of springs have a resilient resistance to lateral bending characteristic and are described here generally as zigzag springs, so that, as used herein, the term zigzag wire is inclusive of both sinuous wire and formed wire.

The support spring 22 has a portion 28 which is formed by a pair of diverging legs 30 and 32 and is therefore referred to hereinafter as the V-shape portion 28. The body spring 20 can be conveniently described as having a lower portion 37 and an upper end portion 38, and an extension 34 of the leg 30 is secured by clips 36 to the upper end portion 38, as shown in FIGS. 1 and 2. The upper end of the leg 32 is formed with an extension 40 which extends in generally the same direction as the body spring 20 in that the extension 40 extends generally in a direction between the rails 14 and 16. The extension 40 consists of a first torsion bar 42 (FIG. 3), which consti' tutes the endmost torsion bar in the support spring leg 32, a second torsion bar 44 which is adjacent the endmost torsion bar 42, and a generally U-shape spacer bar 46 which extends between adjacent ends of the torsion bars 42 and 44. The bar 44 is twisted so that the extension 40 is angularly related to the leg 32 for a purpose to appear presently.

The torsion bar 42 terminates in a prong 48 which is inserted in an opening 50 formed in the mounting face 52 of the frame rail 14. As shown in FIGS. 1 and 3, the prong 48 and the opening 50 are located relative to the bottom side 54 of the frame rail 14 such that when the prong 48 is positioned in the opening 50, the torsion bar 44 is located below and spaced outwardly from the lower side 54 of the frame rail 14. Also, the extension 40 is angularly related to the leg 32 such that in the unloaded condition of the spring unit 10 (FIG. 1), the extension 40 lies in a plane parallel to the mounting face 52, and the torsion bar 42 and at least a portion of the spacer bar 46 are in engagement with the rail mounting face 52.

The principal difference between the unit 10 and the spring units illustrated in Patent No. 2,480,667, is that in the patented units, the spring portions corresponding to the extension 40 are in line with the leg 32. Stated other wise, the extension 40 which is angularly related to leg 32 is lacking in the patented units. As a result, in such a construction only the end torsion bar 42 engages the mounting face 52 and the included angle between the support spring legs 30 and 32, indicated at A in FIG. 1, is less than that illustrated in FIG. 1.

When the spring unit 10 is loaded, the load is normally applied in the direction of the arrow L in FIG. 1, causing the spring unit 10 to move to the deflected position shown in FIG. 2. During such deflection, the spring unit 10 is moved through a deflection cycle in which the load L tends to move the torsion bars 24 in the body spring 20 toward each other. In the use of the spring units shown in US. Patent No. 2,480,667, some of this tendency of the torsion bars 24 to move toward each other is relieved by movement of the torsion bar, corresponding to the torsion bar 42 in the spring unit 10, upwardly along the mounting face 52 on the frame rail 14. When the load is relieved, the upwardly moved torsion bar moves downwardly on face 52. This squirming of the torsion bar 42 on the frame rail face 52 causes the objectionable noise.

In the spring unit it), the force transmitted by the supporting spring leg 32 to the extension 4t) at the beginning of the deflection cycle is indicated at F By virtue of the angular relation of the leg 32 and the extension 40, the force F is closer to being perpendicular to the frame rail face 52 than is the case when the extension 46) and the leg 32 are in line, as in the patented units. As a result, the component of the force F which is normal to the face 52, indicated at P is of a greater magnitude and the force component F which is parallel to the frame rail face 52 is of a reduced magnitude, relative to the corresponding force components in the patented units. The force component F and the torsional distortion of torsion bar 44 which increases as load L is applied, cause the spacer bar 46 and bar 42, to bind on the rail face 52-, thus reducing noise causing movement of the spring on face 52-. In cases in which rail 14 is formed of a relatively soft material, such as the illustrated wood, these forces tend to embed the spacer bar 46 in the lower edge of the wooden frame rail 14 and increase the frictional force exerted on bars 42 and 46 by the frame rail face 52. It is the force component F which is reduced in the unit 10 irrespective of whether it is upwardly or downwardly directed in a specific application, that causes the objectionable squirming of the torsion bar 42 on the frame rail face 52.

It can thus be seen that in the use of the. spring unit 10, the force component F tends to embed the spacer bar 46 in the frame rail face 52 so as to increase the frictional force exerted on the spacer bar 46 and the torsion bar 42 by the frame rail 14 thus further reducing anytendency of the torsion bar 42 to move on the face 52. Consequently, during the deflection cycle of the spring unit 10, relative movement between the frame rail face 52 and the unit 10, with the attendant objectionable noise, is eliminated. Furthermore, the shape of the supporting spring 22 with the angular extension 40 provides for an increased angle A thereby stiffening the support spring 22, in so far as its ability to resist the load I. is concerned, so that a lighter gauge wire can be employed in the supporting spring 22 without adversely afiecting its ability to resist loads, thus enabling fabrication of the spring unit 10 at a reduced cost.

FIG. 5 illustrates a modified form a of the spring unit 10 which is similar to the unit 10, in that it includes a body spring and a support spring 22, but which differs from the spring unit 10 in that the supporting spring 22 is substantially inverted relative to its position in the spring unit 10. As a result, the torsion bar 44a in the unit 10a corresponding to the torsion bar 44 in the unit 10 is above and spaced outwardly from the frame rail 14 rather than below it. In operation, the unit 16a functions like the unit 10 without the objectionable noise which has heretofore been found to be unnavoidable. It is to be noted that in both spring units 19 and 1% some squirming of the body spring 20 on lower frame rail 16 takes place. The resulting noise is damped by the proximity of padding 18 to the lower rail 16 so that it has been found that no objectionable noise results.

It is to be understood that while the units 10 and 10a have been illustrated with the separate springs 20 and-22, the formation of the springs and their manner of attachment are subject to many variations while still utilizing the principles of this invention. For example, the upper end portion 33 of the spring 20 can be formed as a part of the spring 22 or it can take the form of a separate spring with the springs 20 and 22 being formed from a single piece of wire. In any event, the resultant advantage described herein, namely, the elimination of noise with an attendant increase in the ability of the supporting spring 22 to resist loads are obtained. It is also to be understood that while the unit 10 has been illustrated and described with particular reference to its inclusion in a vertical seat back assembly, it is also usable in a generally horizontal position as a part of the bench portion of a seating structure. In such case the rail 16 constitutes the front rather than the top rail. Consequently, the terms upper, lower, etc. are intended herein as terms of reference and not terms of limitation.

It will be understood that the spring unit which is herein disclosed and described is presented for purposes of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claims.

What is claimed is:

I. In a seating structure which includes spaced frame rails, a load supporting spring unit attached to and extending between said rails, said spring unit being of a zigzag wire construction having spaced torsion bars connected by spacer bars, one end of said unit being attached to one face of a frame rail so that the endmost torsion bar at said one end is in a plane parallel to and in engagement with said one face, said unit having a torsion bar adjacent to said endmost torsion bar disposed substantially in said plane and outwardly adjacent one edge of said face, a spacer bar extending between said end-most and adjacent torsion bars and having at least a portion thereof engaged with said face, said unit extending from said last-mentioned torsion bar at an inclined angle relative to said face so that compressive forces in said unit have a force component transmitted to said adjacent torsion bar in a direction perpendicular to said fa-ce tending to torsionaliy distort said adjacent torsion bar and embed said spacer bar in said face.

2. In a seat structure, upper and lower frame rails, a spring unit mounted on said rails so :as to span the distance t-hereoetween, said unit including an elongated body spring attached at one end to said lower rail, a support spring formed of zigzag wire so that it has spaced torsion bars connected by spacer bars and positioned on the rear side of said body spring adjacent the opposite end thereof, said support spring being of generally V-shape so that it has a pair of angularly related legs, one of said legs being attached to said body spring and the other one of said legs extending away from said body spring and terminating in an extension which is substantially parallel to and engaged with a mounting face of said upper frame rail, said extension being angularly related with respect to said other one of said iegs and being joined thereto by a torsion bar located at the juncture of said extension and said other leg, said juncture torsion bar being located adjacent to and spaced outwardly from one edge of said mounting face, said other leg being at an inclined angle with respect to said mounting face so that on movement of said body spring toward said mounting face said other leg will transmit a force to said juncture torsion bar which is directed such that said torsion bar is urged in a direction to force said extension against said mounting face, said extension consisting of an endmost torsion bar engaged with and pronged into said mounting face and at least one spacer bar extending between said endm-ost juncture torsion bars, whereby on movement of said body spring toward said other frame rail said juncture torsion bar is urged in a direction tending to increase the frictional force between said mounting face and said extension engaged therewith and said juncture torsion bar is torsionally distorted causing binding of said extension on said mounting face to minimize movement thereof on said face.

3. In a seat structure, a pair of spaced frame rails, a spring unit mounted on said rails so as to span the distance therebetwecn, said unit including an elongated body spring attached at one end to one of said rails, a support spring formed of zigzag wire so that it has spaced torsion bars connected by spacer lbars and positioned on one side of said body spring adjacent the opposite end thereof, said support spring being of generally V-shape so that it has a pair of angularly related legs, one of said legs being attached to said body spring and the other one of said legs extending away from 'said body spring and terminating in an extension which is substantially parallel to and engaged with a mounting face of the other one of said frame rails, said extension being angularly related with respect to said other one of said legs so that said other leg is disposed at an inclined angle with respect to said mounting face so that on movement of said body spring toward said mounting face said other leg will transmit a force to said extension which is directed such that said force has a component normal to and directed toward said mounting face, said extension including an endmo-st torsion bar engaged with and secured to said mounting face and a References Cited by the Examiner UNITED STATES PATENTS 2,480,667 8/1949 Neely 26-7-1 X 2,831,531 4/1958 Stine 267-107 3,087,719 4/1963 Flint 267-407 X ARTHUR L. LA POINT, Primary Examiner. 

1. IN A SEATING STRUCTURE WHICH INCLUDES SPACED FRAME RAILS, A LOAD SUPPORTING SPRING UNIT ATTACHED TO AND EXTENDING BETWEEN SAID RAILS, SAID SPRING UNIT BEING OF A ZIGZAG WIRE CONSTRUCTION HAVING SPACED TORSION BARS CONNECTED BY SPACER BARS, ONE END OF SAID UNIT BEING ATTACHED TO ONE FACE OF A FRAME RAIL SO THAT THE ENDMOST TORSION BAR AT SAID ONE END IS IN A PLANE PARALLEL TO AND IN ENGAGEMENT WITH SAID ONE FACE, SAID UNIT HAVING A TORSION BAR ADJACENT TO SAID ENDMOST TORSION BAR DISPOSED SUBSTANTIALLY IN SAID PLANE AND OUTWARDLY ADJACENT ONE EDGE OF SAID FACE, A SPACER BAR EXTENDING BETWEEN SAID ENDMOST AND ADJACENT TORSION BARS AND HAVING AT LEAST A PORTION THEREOF ENGAGED WITH SAID FACE, SAID UNIT EXTENDING FROM SAID LAST-MENTIONED TORSION BAR AT AN INCLINED ANGLE RELATIVE TO SAID FACE SO THAT COMPRESSIVE FORCES IN SAID UNIT HAVE A FORCE COMPONENT TRANSMITTED TO SAID ADJACENT TORSION BAR IN A DIRECTION PERPENDICULAR TO SAID FACE TENDING TO TORSIONALLY DISTORT SAID ADJACENT TORSION BAR AND EMBED SAID SPACER BAR IN SAID FACE. 